• Language: en

Source code for django.core.files.storage

import os
import errno
from datetime import datetime

from django.conf import settings
from django.core.exceptions import SuspiciousFileOperation
from django.core.files import locks, File
from django.core.files.move import file_move_safe
from django.utils.crypto import get_random_string
from django.utils.encoding import force_text, filepath_to_uri
from django.utils.functional import LazyObject
from django.utils.module_loading import import_string
from django.utils.six.moves.urllib.parse import urljoin
from django.utils.text import get_valid_filename
from django.utils._os import safe_join, abspathu
from django.utils.deconstruct import deconstructible


__all__ = ('Storage', 'FileSystemStorage', 'DefaultStorage', 'default_storage')


[docs]class Storage(object): """ A base storage class, providing some default behaviors that all other storage systems can inherit or override, as necessary. """ # The following methods represent a public interface to private methods. # These shouldn't be overridden by subclasses unless absolutely necessary.
[docs] def open(self, name, mode='rb'): """ Retrieves the specified file from storage. """ return self._open(name, mode)
[docs] def save(self, name, content): """ Saves new content to the file specified by name. The content should be a proper File object or any python file-like object, ready to be read from the beginning. """ # Get the proper name for the file, as it will actually be saved. if name is None: name = content.name if not hasattr(content, 'chunks'): content = File(content) name = self.get_available_name(name) name = self._save(name, content) # Store filenames with forward slashes, even on Windows return force_text(name.replace('\\', '/'))
# These methods are part of the public API, with default implementations.
[docs] def get_valid_name(self, name): """ Returns a filename, based on the provided filename, that's suitable for use in the target storage system. """ return get_valid_filename(name)
[docs] def get_available_name(self, name): """ Returns a filename that's free on the target storage system, and available for new content to be written to. """ dir_name, file_name = os.path.split(name) file_root, file_ext = os.path.splitext(file_name) # If the filename already exists, add an underscore and a random 7 # character alphanumeric string (before the file extension, if one # exists) to the filename until the generated filename doesn't exist. while self.exists(name): # file_ext includes the dot. name = os.path.join(dir_name, "%s_%s%s" % (file_root, get_random_string(7), file_ext)) return name
[docs] def path(self, name): """ Returns a local filesystem path where the file can be retrieved using Python's built-in open() function. Storage systems that can't be accessed using open() should *not* implement this method. """ raise NotImplementedError("This backend doesn't support absolute paths.")
# The following methods form the public API for storage systems, but with # no default implementations. Subclasses must implement *all* of these.
[docs] def delete(self, name): """ Deletes the specified file from the storage system. """ raise NotImplementedError('subclasses of Storage must provide a delete() method')
[docs] def exists(self, name): """ Returns True if a file referenced by the given name already exists in the storage system, or False if the name is available for a new file. """ raise NotImplementedError('subclasses of Storage must provide an exists() method')
[docs] def listdir(self, path): """ Lists the contents of the specified path, returning a 2-tuple of lists; the first item being directories, the second item being files. """ raise NotImplementedError('subclasses of Storage must provide a listdir() method')
[docs] def size(self, name): """ Returns the total size, in bytes, of the file specified by name. """ raise NotImplementedError('subclasses of Storage must provide a size() method')
[docs] def url(self, name): """ Returns an absolute URL where the file's contents can be accessed directly by a Web browser. """ raise NotImplementedError('subclasses of Storage must provide a url() method')
[docs] def accessed_time(self, name): """ Returns the last accessed time (as datetime object) of the file specified by name. """ raise NotImplementedError('subclasses of Storage must provide an accessed_time() method')
[docs] def created_time(self, name): """ Returns the creation time (as datetime object) of the file specified by name. """ raise NotImplementedError('subclasses of Storage must provide a created_time() method')
[docs] def modified_time(self, name): """ Returns the last modified time (as datetime object) of the file specified by name. """ raise NotImplementedError('subclasses of Storage must provide a modified_time() method')
@deconstructible
[docs]class FileSystemStorage(Storage): """ Standard filesystem storage """ def __init__(self, location=None, base_url=None, file_permissions_mode=None, directory_permissions_mode=None): if location is None: location = settings.MEDIA_ROOT self.base_location = location self.location = abspathu(self.base_location) if base_url is None: base_url = settings.MEDIA_URL self.base_url = base_url self.file_permissions_mode = ( file_permissions_mode if file_permissions_mode is not None else settings.FILE_UPLOAD_PERMISSIONS ) self.directory_permissions_mode = ( directory_permissions_mode if directory_permissions_mode is not None else settings.FILE_UPLOAD_DIRECTORY_PERMISSIONS ) def _open(self, name, mode='rb'): return File(open(self.path(name), mode)) def _save(self, name, content): full_path = self.path(name) # Create any intermediate directories that do not exist. # Note that there is a race between os.path.exists and os.makedirs: # if os.makedirs fails with EEXIST, the directory was created # concurrently, and we can continue normally. Refs #16082. directory = os.path.dirname(full_path) if not os.path.exists(directory): try: if self.directory_permissions_mode is not None: # os.makedirs applies the global umask, so we reset it, # for consistency with file_permissions_mode behavior. old_umask = os.umask(0) try: os.makedirs(directory, self.directory_permissions_mode) finally: os.umask(old_umask) else: os.makedirs(directory) except OSError as e: if e.errno != errno.EEXIST: raise if not os.path.isdir(directory): raise IOError("%s exists and is not a directory." % directory) # There's a potential race condition between get_available_name and # saving the file; it's possible that two threads might return the # same name, at which point all sorts of fun happens. So we need to # try to create the file, but if it already exists we have to go back # to get_available_name() and try again. while True: try: # This file has a file path that we can move. if hasattr(content, 'temporary_file_path'): file_move_safe(content.temporary_file_path(), full_path) # This is a normal uploadedfile that we can stream. else: # This fun binary flag incantation makes os.open throw an # OSError if the file already exists before we open it. flags = (os.O_WRONLY | os.O_CREAT | os.O_EXCL | getattr(os, 'O_BINARY', 0)) # The current umask value is masked out by os.open! fd = os.open(full_path, flags, 0o666) _file = None try: locks.lock(fd, locks.LOCK_EX) for chunk in content.chunks(): if _file is None: mode = 'wb' if isinstance(chunk, bytes) else 'wt' _file = os.fdopen(fd, mode) _file.write(chunk) finally: locks.unlock(fd) if _file is not None: _file.close() else: os.close(fd) except OSError as e: if e.errno == errno.EEXIST: # Ooops, the file exists. We need a new file name. name = self.get_available_name(name) full_path = self.path(name) else: raise else: # OK, the file save worked. Break out of the loop. break if self.file_permissions_mode is not None: os.chmod(full_path, self.file_permissions_mode) return name def delete(self, name): assert name, "The name argument is not allowed to be empty." name = self.path(name) # If the file exists, delete it from the filesystem. # Note that there is a race between os.path.exists and os.remove: # if os.remove fails with ENOENT, the file was removed # concurrently, and we can continue normally. if os.path.exists(name): try: os.remove(name) except OSError as e: if e.errno != errno.ENOENT: raise def exists(self, name): return os.path.exists(self.path(name)) def listdir(self, path): path = self.path(path) directories, files = [], [] for entry in os.listdir(path): if os.path.isdir(os.path.join(path, entry)): directories.append(entry) else: files.append(entry) return directories, files def path(self, name): try: path = safe_join(self.location, name) except ValueError: raise SuspiciousFileOperation("Attempted access to '%s' denied." % name) return os.path.normpath(path) def size(self, name): return os.path.getsize(self.path(name)) def url(self, name): if self.base_url is None: raise ValueError("This file is not accessible via a URL.") return urljoin(self.base_url, filepath_to_uri(name)) def accessed_time(self, name): return datetime.fromtimestamp(os.path.getatime(self.path(name))) def created_time(self, name): return datetime.fromtimestamp(os.path.getctime(self.path(name))) def modified_time(self, name): return datetime.fromtimestamp(os.path.getmtime(self.path(name)))
[docs]def get_storage_class(import_path=None): return import_string(import_path or settings.DEFAULT_FILE_STORAGE)
[docs]class DefaultStorage(LazyObject): def _setup(self): self._wrapped = get_storage_class()()
default_storage = DefaultStorage()
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